1 files changed, 98 insertions, 0 deletions
diff --git a/mozglue/misc/Sprintf.h b/mozglue/misc/Sprintf.h
new file mode 100644
index 0000000000..4b459de82d
--- /dev/null
+++ b/mozglue/misc/Sprintf.h
@@ -0,0 +1,98 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* Provides a safer sprintf for printing to fixed-size character arrays. */
+
+#ifndef mozilla_Sprintf_h_
+#define mozilla_Sprintf_h_
+
+#include <stdio.h>
+#include <stdarg.h>
+#include <algorithm>
+
+#include "mozilla/Assertions.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/Printf.h"
+
+#ifdef __cplusplus
+
+#  ifndef SPRINTF_H_USES_VSNPRINTF
+namespace mozilla {
+namespace detail {
+
+struct MOZ_STACK_CLASS SprintfAppend final : public mozilla::PrintfTarget {
+  explicit SprintfAppend(char* aBuf, size_t aBufLen)
+      : mBuf(aBuf), mBufLen(aBufLen) {}
+
+  bool append(const char* aStr, size_t aLen) override {
+    if (aLen == 0) {
+      return true;
+    }
+    // Don't copy more than what's left to use.
+    size_t copy = std::min(mBufLen, aLen);
+    if (copy > 0) {
+      memcpy(mBuf, aStr, copy);
+      mBuf += copy;
+      mBufLen -= copy;
+    }
+    return true;
+  }
+
+ private:
+  char* mBuf;
+  size_t mBufLen;
+};
+
+}  // namespace detail
+}  // namespace mozilla
+#  endif  // SPRINTF_H_USES_VSNPRINTF
+
+MOZ_FORMAT_PRINTF(3, 0)
+MOZ_MAYBE_UNUSED
+static int VsprintfBuf(char* buffer, size_t bufsize, const char* format,
+                       va_list args) {
+  MOZ_ASSERT(format != buffer);
+#  ifdef SPRINTF_H_USES_VSNPRINTF
+  int result = vsnprintf(buffer, bufsize, format, args);
+  buffer[bufsize - 1] = '\0';
+  return result;
+#  else
+  mozilla::detail::SprintfAppend ss(buffer, bufsize);
+  ss.vprint(format, args);
+  size_t len = ss.emitted();
+  buffer[std::min(len, bufsize - 1)] = '\0';
+  return len;
+#  endif
+}
+
+MOZ_FORMAT_PRINTF(3, 4)
+MOZ_MAYBE_UNUSED
+static int SprintfBuf(char* buffer, size_t bufsize, const char* format, ...) {
+  va_list args;
+  va_start(args, format);
+  int result = VsprintfBuf(buffer, bufsize, format, args);
+  va_end(args);
+  return result;
+}
+
+template <size_t N>
+MOZ_FORMAT_PRINTF(2, 0)
+int VsprintfLiteral(char (&buffer)[N], const char* format, va_list args) {
+  return VsprintfBuf(buffer, N, format, args);
+}
+
+template <size_t N>
+MOZ_FORMAT_PRINTF(2, 3)
+int SprintfLiteral(char (&buffer)[N], const char* format, ...) {
+  va_list args;
+  va_start(args, format);
+  int result = VsprintfLiteral(buffer, format, args);
+  va_end(args);
+  return result;
+}
+
+#endif
+#endif /* mozilla_Sprintf_h_ */